Anti-shake compensation structure for auto-focus

ABSTRACT

An anti-shake compensation structure is provided. The anti-shake compensation structure includes an auto-focus module driving a lens to move along a light entering path of the lens. The auto-focus module includes a lens holder holding the lens, a coil adjacent to the lens holder, and a magnet corresponding to the coil. The anti-shake compensation structure further includes an outer frame supporting the lens holder, and a compensation driving unit driving the lens to sway relative to the outer frame along a direction not parallel to the light entering path. The compensation driving unit includes a compensation coil corresponding to the magnet.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of co-pending application Ser. No.14/223,100, filed on Mar. 24, 2014, for which priority is claimed under35 U.S.C. §120, the entire contents of which are hereby incorporated byreference.

FIELD OF THE INVENTION

The present invention relates to an anti-shake compensation structurefor auto-focus module, and more particularly to an anti-shakecompensation structure that allows an auto-focus module to sway forwardand rearward or leftward and rightward to thereby precisely compensateshake caused by hands.

BACKGROUND OF THE INVENTION

With the progress in scientific technologies and the modularization andminiaturization of camera lens, it is now possible to produce digitalcameras having a very small volume, and most of currently availablemobile phones are provided with the function of a digital camera. On theother hand, to highlight the differences between the advanced cameradevices and the low-level camera devices, higher image quality and morefunctions, such as highly increased pixels, multi-point auto-focus (AF)function, anti-shake (AS) function, etc., have been further added to theadvanced camera devices.

However, every new function added to the image capturing module of acamera device would necessitate the increase of a corresponding modularmechanism to thereby increase the volume of the image capturing module.Therefore, it has become a target of all image capturing modulemanufacturers to further reduce the volume of the capturing module thathas more functions.

There are various types of auto-focus driving structures for theconventional miniature lens. Among others, the voice coil motor (VCM) isthe currently most widely employed auto-focus driving structure. The VCMincludes an assembly of coils, magnets and plate springs to hold a lensthereto, so that the lens is able to move forward and rearward in anoptical axis direction to thereby achieve the object of auto focusing orzooming. The VCM has the advantages of small volume, low powerconsumption, accurately actuated displacement, and cost-effective, andis therefore very suitable for short-distance driving in miniature lensauto-focusing.

With respect to the anti-shake function, it is achieved mainly throughseveral ways. For example, the imaging element can utilize acompensation movement of a mechanism supporting frame to offset theinfluence of shake during shooting picture on the forming of a blurredimage. Or, the lens can be provided with a mechanical structure toeliminate the shake. Or, two gyro sensors can be used to detect anyvibration of the imaging element in horizontal and vertical directions,and use push by magnetic force to compensate such vibration.

The same inventor of the present invention filed U.S. patent applicationSer. No. 12/630,688 entitled “Anti-shake Auto-focus Modular Structure”on Dec. 3, 2009, and FIG. 1 is an exploded perspective view of theanti-shake auto-focus modular structure disclosed therein. According tothe above-mentioned invention, a movement signal generated by a shakesensor is used to drive the whole auto-focus module to instantaneouslymove horizontally in x-axis or y-axis direction, so as to compensate anyshake caused by hands.

Now, based on the structural design of the above-mentioned invention,the inventor further designs a new anti-shake structure for auto-focusmodule. Unlike the above-mentioned invention that teaches the horizontalmovement of the whole auto-focus module in x-axis direction or y-axisdirection to compensate any shake, the new anti-shake structure in thepresent invention uses a center of the auto-focus module as a fulcrum tosway the auto-focus module leftward, rightward, forward or rearward forcompensating any shake caused by hands, the anti-shake structure istherefore simpler and the effect of shake compensation can be producedmore quickly to satisfy the requirement for an advanced camera lensmodule.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an anti-shakecompensation structure for auto-focus module, which allows theauto-focus module to use a center thereof as a fulcrum to sway forward,rearward, leftward or rightward, in order to compensate shake caused byhands, making the anti-shake structure simpler and more efficient.

To achieve the above and other objects, an anti-shake compensationstructure for auto-focus module is provided and includes an auto-focusmodule driving a lens to move along a light entering path of the lens.The auto-focus module includes a lens holder holding the lens, a coiladjacent to the lens holder, and a magnet corresponding to the coil. Theanti-shake compensation structure further includes an outer framesupporting the lens holder, and a compensation driving unit driving thelens to sway relative to the outer frame along a direction not parallelto the light entering path. The compensation driving unit includes acompensation coil corresponding to the magnet.

To achieve the above and other objects, another technical characteristicof the anti-shake compensation structure according to the presentinvention is that the anti-shake compensation structure further includesan elastic supporting member and a base, and the elastic supportingmember elastically connects the base to the outer frame.

To achieve the above and other objects, a further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the elastic supporting member includes a pivotportion and the base sways relative to the outer frame along thedirection not parallel to the light entering path about the pivotportion.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the anti-shake compensation structure furtherincludes a spring sheet elastically connecting the base to the lensholder.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the compensation driving unit further includesa displacement sensor detecting the displacement of the auto-focusmodule relative to the outer frame, and the displacement sensor and thecompensation coil do not overlap in a view of the light entering path.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the displacement sensor and the coil do notoverlap in the view of the light entering path.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the displacement sensor includes amagneto-resistive (MR) sensor detecting the displacement of theauto-focus module relative to the outer frame.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the anti-shake compensation structure furtherincludes an image sensor, and the image sensor and the lens holder arearranged along the light entering path.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the compensation driving unit further includestwo compensation coils respectively driving the lens to sway relative tothe outer frame along two directions which are not parallel to eachother.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the light entering path and the two directionsare perpendicular to each other.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the auto-focus module further includes twomagnets respectively corresponding to the two compensation coils.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the coil is arranged around the lens holder.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the magnet is arranged on the base.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the compensation coil is arranged on an innersurface of the outer frame.

To achieve the above and other objects, a still further technicalcharacteristic of the anti-shake compensation structure according to thepresent invention is that the displacement sensor detecting thedisplacement of the auto-focus module relative to the outer frame isarranged on an inner surface of the outer frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present inventionto achieve the above and other objects can be best understood byreferring to the following detailed description of the preferredembodiments and the accompanying drawings, wherein

FIG. 1 is an exploded perspective view of an anti-shake auto-focusmodular structure disclosed in U.S. patent application Ser. No.12/630,688;

FIG. 2 is a sectional perspective view of an anti-shake compensationstructure for auto-focus module according to a first embodiment of thepresent invention;

FIG. 3 is a schematic plan view of FIG. 2;

FIG. 4 is a perspective view showing an embodiment of an elasticsupporting member used in the present invention;

FIG. 5 is a schematic plan view of an anti-shake compensation structurefor auto-focus module according to a second embodiment of the presentinvention; and

FIG. 6 is a schematic plan view of an anti-shake compensation structurefor auto-focus module according to a third embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some preferredembodiments thereof and with reference to the accompanying drawings. Itis understood the accompanying drawings are illustrated only forassisting in describing the present invention and not intended to limitthe present invention. For the purpose of easy to understand, elementsthat are the same in the preferred embodiments are denoted by the samereference numerals.

Please refer to FIG. 2 that is a partial sectional perspective view ofan anti-shake compensation structure for auto-focus module according toa first embodiment of the present invention; and to FIG. 3 that is aschematic plan view of FIG. 2. The present invention uses a center of anauto-focus module as a fulcrum to sway the auto-focus module leftwardand rightward on x-axis or forward and rearward on y-axis forcompensating any shake caused by hands, so as to improve the anti-shakeauto-focus modular structure disclosed in U.S. patent application Ser.No. 12/630,688 that horizontally moves an auto-focus module in x-axis ory-axis direction for compensating any shake caused by hands whileshooting a picture.

The anti-shake compensation structure for auto-focus module according tothe first embodiment of the present invention includes an auto-focusmodule 10, an outer frame 20, an elastic supporting member 30, acompensation driving unit 40, and a shake sensor (not shown). A lens 11is held to the auto-focus module 10 for capturing light and image. Thelens 11 and an image sensor 12 are aligned with each other on z-axis,that is, on a line along which light enters into the lens 11. Theauto-focus module 10 drives the lens 11 to move forward and rearward inthe light entering path (i.e. z-axis direction), so that the lens 11 canfocus the captured image on the image sensor 12.

The auto-focus module 10 is preferably a driving structure formed of avoice coil motor (VCM); and includes a lens holder for holding andlocking the lens 11 thereto. A coil 14 is arranged around the lensholder, and the lens holder is connected to a movable portion of atleast one plate spring 15, while the at least one plate spring 15 isconnected at a fixed portion thereof to a base 16. Four magnets 17 arearranged in the base 16 corresponding to the coil 14.

The outer frame 20 encloses the auto-focus module 10. The elasticsupporting member 30 is arranged on an inner upper end of the outerframe 20 and connected to an upper end of the auto-focus module 10, soas to suspend the auto-focus module 10 in the outer frame 20. With theelastic supporting member 30 arranged in the above-described manner, theauto-focus module 10 is allowed to sway forward and rearward or leftwardand rightward with a center of the elastic supporting member 30 actingas a fulcrum.

Please refer to FIG. 4 that is a perspective view showing an embodimentof an elastic supporting member used in the present invention. As shown,the elastic supporting member 30 includes an outer fixed portion 31, afirst inner movable portion 32, and a second inner movable portion 33.The outer fixed portion 31 is fixedly connected to the inner upper endof the outer frame 20; the first inner movable portion 32 is located atan inner side of the outer fixed portion 31, and is connected at twoopposite and symmetrical first pivot portions 321 to the outer fixedportion 31; and the second inner movable portion 33 is located at aninner side of the first inner movable portion 32, and is connected attwo opposite and symmetrical second pivot portions 331 to the firstinner movable portion 32. It is noted the two second pivot portions 331are respectively located at an angular position of 90 degrees relativeto the first pivot portions 321, and the second inner movable portion 33is connected to the upper end of the auto-focus module 10.

The first inner movable portion 32 allows the auto-focus module 10 tosway leftward and rightward on x-axis; and the second inner movableportion 33 allows the auto-focus module 10 to sway forward and rearwardon y-axis. Alternatively, the present invention can be differentlydesigned for the first inner movable portion 32 to allow the auto-focusmodule 10 to sway forward and rearward on y-axis; and for the secondinner movable portion 33 to allow the auto-focus module 10 to swayleftward and rightward on x-axis.

Please refer to FIGS. 2 and 3 at the same time again. The compensationdriving unit 40 is located behind the auto-focus module 10 for drivingthe auto-focus module 10 to sway leftward and rightward on x-axis orforward and rearward on y-axis within the outer frame 20, so as tocompensate any image deviation due to shake caused by hands.

The compensation driving unit 40 includes a compensation magnet assembly41, a compensation coil assembly 42, and a displacement sensor assembly.The compensation magnet assembly 41 is arranged beneath an outer bottomface of the auto-focus module 10, and includes at least one x-axiscompensation magnet and at least one y-axis compensation magnet.

The compensation coil assembly 42 is arranged on an inner bottom face ofthe outer frame 20, and includes at least one x-axis compensation coiland at least one y-axis compensation coil corresponding to the x-axiscompensation magnet and the y-axis compensation magnet, respectively,for separately generating an electromagnetic field to drive theauto-focus module 10 to tilt on x-axis or y-axis.

The displacement sensor assembly is arranged on a central area of theinner bottom face of the outer frame 20, and includes a displacementsensor 43 and a sensing magnet 44. Preferably, the displacement sensor43 is a two-axis sensing IC. The displacement sensor 43 corresponds tothe sensing magnet 44 for detecting a volume of displacement in x-axisdirection or y-axis direction, so that the auto-focus module 10 can bedriven to reach at a precise compensation position.

Preferably, the displacement sensor 43 can be a Hall sensor, amagneto-resistive (MR) sensor, a fluxgate sensor, an optical positionsensor, or an optical encoder.

An advanced hand-held device is generally provided with a shake sensor,such as a Gyro sensor, an accelerometer, etc., for generating a shakesignal in response to any shake of the hand-held device and sending theshake signal to the compensation driving unit for use as a basis todetermine an angle by which the auto-focus module should be driven totilt on x-axis or y-axis. The present invention may utilize the shakesensor provided in the advanced hand-held device in the case the presentinvention is provided on the hand-held device. Alternatively, theanti-shake compensation structure of the present invention can bedirectly provided with a shake sensor.

FIG. 5 is a schematic plan view of an anti-shake compensation structurefor auto-focus module according to a second embodiment of the presentinvention, in the second embodiment, the compensation driving unit 40includes a compensation coil assembly 42, and a displacement sensor 43.And, the magnets 17 in the auto-focus module 10 are also used as thecompensation magnet assembly. That is, the compensation driving unit 40and the auto-focus module 10 use the same set of magnets.

The compensation coil assembly 42 is arranged on an inner wall surfaceof the outer frame 20, and includes at least one x-axis compensationcoil and at least one y-axis compensation coil separately correspondingto one of the magnets 17 in the auto-focus module 10 for respectivelygenerating an electromagnetic field to drive the auto-focus module 10 totilt on x-axis or y-axis.

The displacement sensor 43 is arranged on the inner bottom face of theouter frame 20, and includes an x-axis sensor and a y-axis sensorseparately corresponding to one of the magnets 17 in the auto-focusmodule 10 for detecting a volume of displacement in x-axis direction ory-axis direction, so that the auto-focus module 10 can be driven toreach at a precise compensation position.

FIG. 6 is a schematic plan view of an anti-shake compensation structurefor auto-focus module according to a third embodiment of the presentinvention. In the third embodiment, the compensation driving unit 40includes a compensation magnet assembly 41, a compensation coil assembly42, and a displacement sensor 43. The compensation magnet assembly 41 isarranged on an outer lower end of the auto-focus module 10, and includesat least one x-axis compensation magnet and at least one y-axiscompensation magnet.

The compensation coil assembly 42 is arranged on an inner lower end ofthe outer frame 20, and includes at least one x-axis compensation coiland at least one y-axis compensation coil corresponding to the x-axiscompensation magnet and the y-axis compensation magnet, respectively,for separately generating an electromagnetic field to drive theauto-focus module to tilt on x-axis or y-axis.

The displacement sensor 43 is arranged on the inner bottom face of theouter frame 20, and includes an x-axis sensor and a y-axis sensorcorresponding to the x-axis compensation magnet and the y-axiscompensation magnet, respectively, for detecting a volume ofdisplacement in x-axis direction or y-axis direction, so that theauto-focus module 10 can be driven to reach at a precise compensationposition.

The present invention has been described with some preferred embodimentsthereof and it is understood that many changes and modifications in thedescribed embodiments can be carried out without departing from thescope and the spirit of the invention that is intended to be limitedonly by the appended claims.

What is claimed is:
 1. An anti-shake compensation structure, comprising:an auto-focus module, driving a lens to move along a light entering pathof the lens, comprising: a lens holder, holding the lens; a coil,adjacent to the lens holder; a magnet, corresponding to the coil; anouter frame, supporting the lens holder; and a compensation drivingunit, driving the lens to sway relative to the outer frame along adirection not parallel to the light entering path, wherein thecompensation driving unit comprises a compensation coil corresponding tothe magnet.
 2. The anti-shake compensation structure of claim 1, whereinthe anti-shake compensation structure further comprises an elasticsupporting member and a base, and the elastic supporting memberelastically connects the base to the outer frame.
 3. The anti-shakecompensation structure of claim 2, wherein the elastic supporting membercomprises a pivot portion and the base sways along the direction notparallel to the light entering path about the pivot portion.
 4. Theanti-shake compensation structure of claim 3, wherein the anti-shakecompensation structure further comprises a spring sheet elasticallyconnecting the base to the lens holder.
 5. The anti-shake compensationstructure of claim 1, wherein the compensation driving unit furthercomprises a displacement sensor detecting the displacement of theauto-focus module relative to the outer frame, and the displacementsensor and the compensation coil do not overlap in a view of the lightentering path.
 6. The anti-shake compensation structure of claim 5,wherein the displacement sensor and the coil do not overlap in the viewof the light entering path.
 7. The anti-shake compensation structure ofclaim 6, wherein the displacement sensor comprises a magneto-resistive(MR) sensor detecting the displacement of the auto-focus module relativeto the outer frame.
 8. The anti-shake compensation structure of claim 1,wherein the anti-shake compensation structure further comprises an imagesensor, and the image sensor and the lens holder are arranged along thelight entering path.
 9. The anti-shake compensation structure of claim1, wherein the compensation driving unit further comprises twocompensation coils respectively driving the lens to sway relative to theouter frame along two directions which are not parallel to each other.10. The anti-shake compensation structure of claim 9, wherein the lightentering path and the two directions are perpendicular to each other.11. The anti-shake compensation structure of claim 9, wherein theauto-focus module further comprises two magnets respectivelycorresponding to the two compensation coils.
 12. The anti-shakecompensation structure of claim 1, wherein the coil is arranged aroundthe lens holder.
 13. The anti-shake compensation structure of claim 1,wherein the anti-shake compensation structure further comprises anelastic supporting member and a base, and the elastic supporting memberelastically connects the base to the outer frame, and the magnet isarranged on the base.
 14. The anti-shake compensation structure of claim1, wherein the compensation coil is arranged on an inner surface of theouter frame.
 15. The anti-shake compensation structure of claim 1,wherein the compensation driving unit further comprises a displacementsensor detecting the displacement of the auto-focus module relative tothe outer frame, and the displacement sensor is arranged on an innersurface of the outer frame.